Improvement in upright steaivi-boilers



`GEORGE W. RAWSON, OF OAMBRIDGEPOBT, ASSIGNOR TO HIMSELF AND MICHAEL HITTINGER, OF SOMERVILLE, MASSACHUSETTS.

IMPROVEMENT' IN UPRIGHT STEAM-BOWERS.

Specication forming part of Letters Patent N0. llh0,729, dated July 8, 1873 application filed December 18, 1872.

To all whom it may concern:

Be it known that I, GEORGE W. Rawson, of Gambridgeport, of the county of Middlesex and State o .f Massachusetts, have invented a new and useful Improvement in Upright Steam Boilers or Generators; and do hereby declare the same to be fullyT described in the following v specilication and represented in the accompanying drawings, of which- Figure l is a vertical section, and Fig. 2 a horizontal section of one of myimproved boilers, the plane of section of the latter figure being taken just above the crown-sheet of the fire-place.

In such drawings, A denotes the lire-place, cylindrical in form and having a series of tubes, B, extended vertically from it and through its top or crown-sheet c, and a water and steam chamber, O, to and through the top of the latter and into a conical smoke-stack, D, erected over such chamber O in manner as shown. Within the said stack, and concentric therewith, and opening out ofthe chamber O, is a steam-superheatin g dome or vessel, E,pro vided with a discharge-pipe, F, arranged as shown. In the central part of the chamber C is a circulation-tube, G, supported by bracerods H extended from it both to the top and to the bottcmlof the chamber. The said pipe does not extend down tothe bottom of the chamber (l, and the top of the pipe is to be below the level at which the water is to stand in the chamber while the boiler may be generating steam.

The object of this pipe is to cause, while the water in the boiler is being heated, a central downward current of water to be formed and to strike or iinpinge upon the crown-seat at its center and about such, in order to prevent the accumulation thereon of calcareous or other nimproper deposits which, without the pipe, will take place. Furthermore, the pipe and its brace or support rods greatly strengthen the boiler and counteract the strain on its upper head induced by the upward pressure of the steam in the dome. The stack of tubes B I arrange with di ametric passages H', arranged through it and the boiler in manner as represented in Fig. 2, each of such passages, at its two opposite ends and just above the crownsheet a, being provided with spy-holes s s formed through the sides of the boiler and provided with suitable caps, covers, or stoppers t t.

By removing the stoppcrs a person may see through the passages and over the center of the crown-sheet and remove any accumula` tions thereon by means of a scraper introduced into one of the holes, the opposite hole serving to light the passage. By having the steamsuperheating dome or vessel E arranged within the smoke-stack it becomes subjected to the heat thereof, whereby the steam in the chamber, instead of being liable to be condensed, becomes superheated.

I make no claim to the combination of a steam receiver or dome with a boiler, such being in use on locomotive engines 3 nor do I claim a boiler with upright tubes or ilues going through it and opening ont of the replace; but

What I claim as my invention is as follows:

l. The circulation-tube G and the brace-rods H at its opposite ends, arranged within the water and steam chamber, or interior of the 

